Blue Lake beans are a highly esteemed variety of Phaseolus vulgaris, commonly known as green beans or snap beans, prized for their rich flavor and tender texture. Their popularity stems largely from their quality when canned, but they are equally enjoyed fresh. Older green bean varieties often had a “string,” a tough, fibrous suture that required manual removal before cooking. Modern breeding efforts aimed to eliminate this undesirable characteristic to improve the eating experience.
The Stringless Revolution in Blue Lake Beans
Modern Blue Lake cultivars are considered stringless. This quality is the result of focused agricultural breeding programs, which began to successfully remove the fibrous string in the early 20th century, culminating in popular stringless strains in the 1950s and 1960s. The literal “string” is a bundle of tough vascular tissue that develops along the two seams of the bean pod. Eliminating this trait meant that the entire pod could be cooked and eaten without needing to be “strung.”
The introduction of stringless types like ‘Stringless Blue Lake FM-1K’ revolutionized commercial and home canning because they significantly reduced preparation time. While older varieties sometimes still possessed this string, the strains sold today are specifically bred to be stringless. This genetic modification is now an inherent characteristic of the Blue Lake bean group, ensuring a consistently tender product.
Understanding Bush and Pole Varieties
Blue Lake is a group of closely related cultivars, categorized by their growth habit: bush or pole. Both the bush and pole forms of modern Blue Lake beans possess the same desirable stringless trait. Bush varieties are determinate, growing into a compact, self-supporting plant, typically reaching about 18 to 24 inches in height. They tend to produce their entire yield in a concentrated period, making them suitable for mechanical harvesting and large-batch processing.
Pole varieties are indeterminate, growing as vigorous, vining climbers that can reach six to eight feet high, requiring a trellis or support structure. Pole beans offer a significant advantage to gardeners by providing a continuous, extended harvest throughout the growing season. Despite these differences in growth pattern, both the bush and pole Blue Lake forms deliver the same high-quality, stringless pods with superior flavor.
Factors That Influence Texture and Quality
While modern Blue Lake beans are genetically stringless, a pod can still become tough or fibrous due to environmental factors. The primary cause of this toughness is over-maturity, which occurs when the bean is left on the vine too long, allowing the seeds inside to swell and the pod walls to become pithy. As the seeds develop, the pod deposits more cellulose and lignin, increasing its fibrousness.
Heat and drought stress during the growing period also accelerate the development of tough fibers, regardless of the variety’s stringless status. To maintain the bean’s characteristic tenderness, harvest the pods when they are firm, bright green, and before the outline of the seeds is visible through the pod wall. Improper storage, such as warm temperatures or low humidity, can lead to rapid water loss, causing the beans to shrivel and become less tender.